6/30/2023 0 Comments A piezo buzzer![]() ![]() Because of the coil’s inductance, the diode shown in the diagram is needed to clamp the flyback voltage when the transistor is turned off quickly.įigure 4. The switch is typically a bipolar transistor or FET and is used to amplify the excitation waveform. ![]() ![]() In addition to basic continuous or pulsed sounds, you can generate sounds such as multi-tone warnings, sirens or chimes.įigure 4 shows the application circuit for a magnetic transducer. ![]() With no driving circuitry built in, a transducer gives you the flexibility to achieve a variety of sounds using various frequencies or arbitrary waveshapes. An indicator buzzer produces sound when a dc voltage is applied. This means that multi-frequency sounds such as sirens or chimes are not possible with indicator buzzers.įigure 3. While you only need to apply a dc voltage, one can only get a continuous or pulsed audio signal since the frequency is fixed internally. This simplifies circuit design (figure 3), enabling a plug-and-play approach, in exchange for reduced flexibility. The decision of whether to choose an indicator or transducer type is guided by the range of sounds required and the design of the associated circuitry to drive and control the buzzer.Īn indicator comes with driving circuitry built into the device. However, if loudness is a key requirement, piezo buzzers can typically produce a higher Sound Pressure Level (SPL) than magnetic buzzers but also tend to have a larger footprint. The characteristics of the drive signal you have available can influence whether you choose a magnetic or piezo buzzer for your application. On the other hand, while piezo buzzers exhibit a reasonably linear relationship between the input signal strength and the output audio power, the audio power of magnetic buzzers fall sharply with diminishing signal strength. The piezo buzzer is modeled as a capacitor, whereas the magnetic buzzer is modeled as a coil in series with a resistor.įor both types, the frequency of the resulting audible tone is determined by the frequency of the driving signal and can be controlled over a wide range. In contrast to the magnetic buzzer, the piezo buzzer is a voltage-driven device the operating voltage is usually higher and may be between 12V and 220V, while the current is less than 20mA. A voltage applied across these electrodes causes the piezoelectric material to deform, resulting in the movement of air that can be detected as sound. A disk of piezoelectric material is supported at the edges in an enclosure and electrical contacts are fabricated on the two sides of the disk. Magnetic buzzer construction and operating principle.įigure 2 shows the elements of a piezo buzzer. The current through the coil is determined by the applied voltage and the coil impedance.įigure 1. This deflection of the disk causes air in the vicinity to move, and this is interpreted as sound by the human ear. When the current is passed through the coil, the disk is attracted towards the coil and returns to its normal position when the current is not flowing. The applied voltage can be as low as 1.5V or up to about 12V.Īs figure 1 shows, the mechanism comprises a coil and a flexible ferromagnetic disk. Magnetic buzzers are essentially current-driven devices, typically requiring more than 20mA to operate. Let us take a look at the principles behind the different mechanisms and then consider whether the magnetic or piezo type (and the choice of indicator or actuator) could be right for your project. You can also choose between indicator and transducer types, depending on the sounds you want and the circuit-design skills available to you. Your choice can depend on the characteristics of the drive signal, or the output audio power required and physical space available. Fundamentally, a buzzer is usually either a magnetic or piezoelectric type. ![]()
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6/30/2023 0 Comments Charles proxy 3.11.7 download![]() ![]() We take here the opportunity to warmly thank all the members of the CLOUD COMPUTING 2015 technical program committee, as well as the numerous reviewers. We were very pleased to receive top quality contributions. The conference had the following tracks: Cloud computing Computing in virtualization-based environments Platforms, infrastructures and applications Challenging features Similar to the previous edition, this event attracted excellent contributions and active participation from all over the world. The technology foundations for cloud computing led to a new approach of reusing what was achieved in GRID computing with support from virtualization. Cloud computing is a normal evolution of distributed computing combined with Service- oriented architecture, leveraging most of the GRID features and Virtualization merits. A complementary target was to identify the open issues and the challenges to fix them, especially on security, privacy, and inter- and intra-clouds protocols. ![]() The Sixth International Conference on Cloud Computing, GRIDs, and Virtualization (CLOUD COMPUTING 2015), held between March 22-27, 2015 in Nice, France, continued a series of events targeted to prospect the applications supported by the new paradigm and validate the techniques and the mechanisms. Finally, by addressing the limitations of current research works, we present some open issues, which will determine the future research direction for the Fog computing paradigm. We also discuss existing research works and gaps in resource allocation and scheduling, fault tolerance, simulation tools, and Fog-based microservices. Next, a taxonomy of Fog computing is proposed by considering the requirements of the Fog computing paradigm. From this, the role of each component will be defined, which will help in the deployment of Fog computing. Then, we investigate numerous proposed Fog computing architecture and describe the components of these architectures in detail. This paper starts with an overview of Fog computing in which the definition of Fog computing, research trends, and the technical differences between Fog and cloud are reviewed. This survey will help the industry and research community synthesize and identify the requirements for Fog computing. Fog computing research is still in its infancy, and taxonomy-based investigation into the requirements of Fog infrastructure, platform, and applications mapped to current research is still required. ![]() One of the key challenges in running IoT applications in a Fog computing environment are resource allocation and task scheduling. These Fog devices are located in close proximity to users and are responsible for intermediate computation and storage. In general, in the Fog computing environment, IoT devices are connected to Fog devices. To address this issue, Fog computing, which resides in between cloud and IoT devices, was proposed. However, processing IoT application requests on the cloud exclusively is not an efficient solution for some IoT applications, especially time-sensitive ones. Data generated from IoT devices are generally processed in a cloud infrastructure because of the on-demand services and scalability features of the cloud computing paradigm. In IoT environments, connected things generate a huge amount of data, which are generally referred to as big data. Emerging technologies like the Internet of Things (IoT) require latency-aware computation for real-time application processing. ![]() 6/30/2023 0 Comments Teorex photostitcher review![]() ![]() It uses all available CPU processing which makes other apps come to a crawl.Hitting command + period stopped the process. There is no cancel button after the stitching process has started.Multiple warp surfaces create unique panoramic pictures.The demo version does not allow you to save the final image. Price: Currently $19.99 from the Mac App Store or a demo version from their website. So having this handy app from Teorex helped me to create share-worthy panoramas. The consumer grade major brand name camera I purchased a little over a year ago did not come with a panoramic option like my other camera did. However, the built-in stitching software on those cameras along with what is available on the newest smartphones are almost always unable to stitch photos without creating contrast banding or other visual errors. Most modern consumer cameras and smartphones come with a panoramic stitching option built-in. Consumer level cameras can produce wide photos, so three should be good enough to create a superb panoramic. If you want the stitching process to go a lot faster, having only three photos in queue was the sweet spot. While this MBP is no slouch, I am sure a Mac Pro or a MacBook Pro with a quad-core i7 processor would stitch the photos faster. This app was tested on a MacBook Pro Core 2 Duo 2.53Ghz running the newest Mac OS X 10.7.5 with 4GB of ram. It would be nice if the progress bar showed a percentage instead. The indication window has a continuously forward rotating progress bar. I found that stitching more than six photos with a greater than a 30% overlap kept the stitching progress window open for more than what seemed like a few minutes. Photostitcher worked well with just a few photos in the queue. ![]() As long as the images have about a 30% overlap, it will automatically figure out where each picture fits. The stitching process is smart enough to put the photos together without each imported picture needing sequential numbers. Smartphone apps that create panoramic photos have not been able to produce pictures this clear. My photos of a pool event on a bright day with people moving around yielded a panoramic photo with no discernible ghosting. The app deals really well with shadows, lines in concrete, people and objects that are placed at angles. All I had to do was place the box over what I wanted and click once on the crop icon. The cropping option is always overlaid over the image. In less than a minute for each rough panoramic, selecting alternate warp surfaces will result in unexpected photographic serendipity.Ĭropping the rough panoramic photos is made really easy. This is where the fun of Photostitcher comes into the picture. If your images are anything other than flat, definitely experiment with the warp surface style options. If your original images are flat, the warp surface to choose is spherical. Clicking on ok continues the relatively quick process of stitching at about 45 seconds. To create a simple panoramic photo, select the spherical option. There are six options to choose from under warp surface that include, plane, cylindrical, spherical, fisheye and stereographic. This brings up a window asking which format you would like to stitch the images with. To start the process of stitching a few photos, click on the play button next to the crop option. Once inside of the app, the photos are displayed in a scrollable list with large previews. Tap the plus button once and you are then able to select pictures from anywhere on your Mac. Photostitcher for Mac by Teorex has an easy to use method to import photos with just a few clicks. For the rest of us that want to create a similar effect with a group of photos on a Mac, that is where Photostitcher comes into the picture. ![]() Do you ever wonder how photographers create wide panoramas of amazing vistas or landscapes? Most top photogs have special lenses and other camera gear that cost tens of thousands of dollars. ![]() 6/30/2023 0 Comments Easy seal holiday gift bags![]() ![]() We loved the snappy Edamame Senbei, a salty-sweet cracker dusted with soybean powder. Textures ranged from crispy to chewy to melt-in-your-mouth cotton-candy wispy. ![]() ![]() The flavors of the crackers, puffs, and candies inside were alternately zingy, tart, sweet, and salty. The Seasons of Japan box has 22 snacks, which felt like enough to last one person one to two weeks or to tide over several people for a few days. Some items that were popular with our tasters include tender matcha-powdered mochi, crisp senbei (rice crackers) encrusted with sugar, and strawberry shortcake gummies shaped like slices of cake. The box includes a fun array of snacks that mostly skew sweet. 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Unfortunately, Amazon can change prices at any time- I am sorry if the price has changed since I wrote this post! ![]() 6/30/2023 0 Comments Case scala![]() ![]() Version 2 - leads to a compiler warningĪgain, compile the code with scalac, but right away you’ll see a warning message: Next, make a minor change to the code, replacing the integer literal 2 with a value: This shows that Scala was able to optimize your match expression to a tableswitch. The output from this command shows a tableswitch, like this: Next, disassemble that file with this javap command: First, place the following code in a file named SwitchDemo.scala:Ĭompiling this class produces no warnings and creates the output file SwitchDemo.class. The effect of the annotation is demonstrated with a simple example. If present, the compiler will verify that the match has been compiled to a tableswitch or lookupswitch, and issue an error if it instead compiles into a series of conditional expressions.” “An annotation to be applied to a match expression. Here’s the official description from the annotation documentation: ![]() When a value is given to the expression, it can jump directly to the result rather than working through the decision tree. This annotation provides a warning at compile time if the switch can’t be compiled to a tableswitch or lookupswitch.Ĭompiling your match expression to a tableswitch or lookupswitch is better for performance, because it results in a branch table rather than a decision tree. When writing simple match expressions like this, it’s recommended to use the annotation. A more functional approach returns a value from a match expression:Ĭase _ => "Invalid month" // the default, catch-all That example shows how to take an action based on a match. catch the default with a variable so you can print itĬase whoa => println("Unexpected case: " + whoa.toString) To use a Scala match expression like a Java switch statement, use this approach: You have a situation in your Scala code where you want to create something like a simple Java integer-based switch statement, such as matching the days in a week, months in a year, and other situations where an integer maps to a result. This is Recipe 3.7, “How to use a Scala match expression like a switch statement.” Problem This is an excerpt from the 1st Edition of the Scala Cookbook (partially modified for the internet). show more info on classes/objects in repl. ![]() |